What is CSS percentage unit?
The percentage unit (%) is relative to the parent element's corresponding dimension. For width, it's relative to parent's width; for height, to parent's height.
Frequently Asked Questions about percentage units
How do percentages work with margins and padding?
For horizontal margins and padding, percentages are relative to the parent's width. For vertical margins and padding, they're also relative to the parent's width, not height.
When should I use percentage over viewport units?
Use percentages when you want elements to scale relative to their container rather than the viewport.